The aim of this work was to assess the effects of a high-fat diet enriched in Ca, which accompanies lower body fat deposition, on mineral depots, as well as to assess the potential role of adaptive thermogenesis in mice. Male mice were fed ad libitum a high-fat (43 %) diet with a Ca content of 4 g/kg from calcium carbonate (control group) or 12 g/kg (42 % from milk powder and the rest from calcium carbonate) (Ca group) for 56 d. Body weight, food intake and urine were periodically collected. Tissue samples were collected when the mice were killed and the composition was determined. Expression of uncoupling proteins was determined by Western blotting. Mineral content was measured by flame atomic absorption spectrometry. Lower body weight gain and fat accretion was found in the Ca group. This could not be attributable to lower gross energy intake or to activation of adaptive thermogenesis. Although significant urine mineral loss was found in the Ca group, preservation of mineral depots in bone was observed. Our data support the fact that adding more Ca to the diet, using a combination of calcium carbonate plus milk powder containing among other things higher Zn and Mg, contributes to counteracting obesity and improving lipid metabolism.Dietary calcium: Zinc: Magnesium: Obesity Observational and epidemiological data have shown that a low-Ca diet may be a risk factor for obesity development, and beneficial aspects of milk components on metabolic syndrome are gaining strength (1,2) , even though intervention trials have yielded inconsistent results to date (3) .The molecular mechanisms responsible for the impact of dairy products on body weight and fat have been studied in animal models with important contributions from the group of Zemel (4) . Using a transgenic animal model (over-expressing agouti protein under the control of the aP2 promoter), Zemel and co-workers showed that dietary Ca could influence fat deposition by direct modulation on adipocyte metabolism, increasing thermogenesis and lipolysis and decreasing lipogenesis following a high-Ca diet (5,6) . However, in normal mice, activation of thermogenesis does not seem to be responsible for the lower rate of weight gain seen with a high-fat diet enriched with dairy Ca (7) .Minerals have been suggested to beneficially modulate cardiovascular risk factors (8,9) . However, there are few data available concerning dietary mineral interactions. The aim of the present work was to assess the effects of a high-fat diet enriched in Ca on body fat and mineral bone retention, particularly on Ca, Mg and Zn, as well as to assess the potential involvement of adaptive thermogenic mechanisms in mice.
Experimental methods
Animals and dietsTwelve male mice (C57BL/6J) (Charles River, Spain) weighing approximately 21 g were housed in groups of three and kept in a single metabolic cage throughout the experiment under controlled conditions. After a 1-week adaptation, mice received ad libitum either a control diet or a high-Ca diet (Research Diets Inc., New Brunswick, NJ, USA) for ...
